An internal combustion engine includes a fuel nozzle for injecting a fuel into a combustion chamber, and a plasma igniter for generating one or more pluralities of free radicals within the chamber, and initiating a flame to ignite the fuel. The igniter protrudes into the chamber. A method of igniting a fuel within a combustion chamber and controlling combustion phasing includes injecting a first portion of the fuel into the combustion chamber, energizing the plasma igniter to generate one or more pluralities of free radicals, each plurality having a known voltage, subsequently injecting a second portion of the fuel into the combustion chamber, and closely coupling activation of the plasma igniter with the second injection to ignite the fuel. Combustion phasing of the ignition event is controlled by controlling the number and voltage of the pluralities of free radicals generated by the plasma igniter.

An electronic ignition system for a portable gasoline tool includes a voltage boosting device, a spark plug connected with an output of the voltage boosting device, a DC power source, and a controller electrically connected with the DC power source and connected with the voltage boosting device. The controller controls an ignition voltage and an ignition advance angle. A related portable gasoline tool includes a body, a cylinder located in the body, a piston movable to and fro within the cylinder, a crankshaft co-moved with the piston, and a flywheel located on the body and driven by the crankshaft to rotate.

Methods and systems are provided for reducing fouling of a spark plug in a cylinder of a variable displacement engine configured to propel a vehicle. In one example, a method includes in response to deactivation of a cylinder or cylinders of the engine, providing spark to the cylinder or cylinders at a predefined position of a piston or pistons coupled to the cylinder or cylinders, respectively, where the predefined position comprises the piston or pistons being within a threshold of a bottom dead center position. In this way, spark plug fouling may be reduced or eliminated during conditions of cylinder deactivation.

Systems and methods for determining operation of a cylinder deactivating/reactivating device are disclosed. In one example, degradation of the cylinder deactivating/reactivating device is based on intake manifold oxygen concentration.

An ignition coil includes an ignition circuit having a first winding and a second winding, a controller in communication with the ignition circuit, and a light. The ignition circuit is configured to output an ignition timing signal. The controller is configured to establish a rule that limits an engine speed to a maximum engine speed to be provided by the ignition timing signal. The light is configured to illuminate and indicate the maximum engine speed in response to an output signal from the controller.

Methods and systems are provided for estimating exhaust gas recirculation (EGR) flow in an engine including an EGR system. In one example, a method may include operating the EGR system in an open loop feed forward mode based on an intake carbon di oxide sensor output above a threshold engine load and/or when a manifold absolute pressure (MAP) is above a threshold pressure, and operating the EGR system in a closed loop feedback mode based on a differential pressure sensor output when the engine load decreases below the threshold load and/or when the MAP decreases below the threshold pressure.

A method and a controller for controlling spark timing in a cold start condition for an engine in a vehicle propulsion system. The method includes determining whether the engine is in a cold start condition, and advancing spark timing before top dead center in a combustion cycle such that combustion heat is primarily received by a surface in a combustion chamber in the engine if the engine is in a cold start condition.

A method and a controller for controlling spark timing in a cold start condition for an engine in a vehicle propulsion system. The method includes determining whether the engine is in a cold start condition, and advancing spark timing before top dead center in a combustion cycle such that combustion heat is primarily received by a surface in a combustion chamber in the engine if the engine is in a cold start condition.

Methods and systems are provided for identifying degradation of active engine mounts coupled to a vehicle engine. By correlating the monitored vibrational pattern to a selected active mounts operating mode, the conditions of active engine mounts may be distinguished. Timely diagnosis of active engine mounts may improve active engine mount health and prevent noise, vibration, and harshness (NVH) issues.

Methods and systems are provided for improving the detection and mitigation of high speed pre-ignition. In one example, high speed pre-ignition is detected based on concurrent or sequential changes in an integrated knock sensor output in a knock window as well as a pre-ignition window. The high speed pre-ignition is addressed using cylinder fuel deactivation and/or engine load limiting to reduce the risk for run-away pre-ignition.